Investigation Of NiSi_n And Y_nAl Clusters Based On Density Functional Theory

In view of that more and more clusters have been synthesized successfully, we can't obtain full infornzation about the geometries and electronic qualities from the experiments, while theoretical methods become the most effective approach to study clusters. So in this paper, Based on the first principles, the geometries, stabilities, electronic and magnetic properties of NiSin(n=1~13) and YnAl(n=1~14) clusters have been systematically investigated by using density functional theory (DFT) with generalized gradient approximation (GGA).Firstly,NiSin(n=1~13) clusters have been systematically investigated by using the density functional theory with generalized gradient approximation. The growth patterns, electronic and magnetic properties of NiSin clusters with different spin multiplicities are discussed in detail. The calculated results indicate that the stable NiSin+1 geometries are generated with one Si atom being face capped on the stable NiSin clusters. The doping of Ni atom can enhance the stability of the Sin clusters, and the NiSi10 cluster is the most stable specie of all different-sized clusters. The total spin magnetic moment of NiSin cluster is about 2μB at n=1, 2, and the spin magnetic moment of NiSin cluster is quenched when n surpasses 2, the strong hybridization between Ni 3d, 4s, 4p and Si 3s, 3p states might be one major reason for quenching the magnetic moment of NiSin cluster.Secondly,we choose the Al atom as impurity and study the grow patterns, relative stabilities, HOMO-LUMO gaps, charge transfer and magnetic properties of YnAl (n=1~14) clusters. It was found that the most stable structures of YnAl clusters generally keep the analogous frameworks as the ground-state geometries of Yn+1 clusters except for Y9Al cluster. Doping of the Al atom contributes to strengthen the stabilities of the yttrium framework. In addition, the relative stability of Y12Al are the strongest among all different sized YnAl clusters, which might stem from its highly symmetric geometry. Doping of the Al atom decreases the average magnetic moments of the most Yn clusters. Especially, the magnetic moment is completely quenched after doping Al in the Y13, which is ascribed to the disappearance of the ininerant 4d electron spin exchange effect. Finally, the frontier orbitals properties of YnAl are also discussed.